How does diabetes cause foot amputations?

https://www.healthline.com/health/diabetes/diabetes-amputation#is-amputation-needed

Basically diabetes, if left unmanaged, can result in a shrinking of blood vessels which limits blood flow to extremities. If this gets bad enough, it can result in tissue damage or even tissue death. If that occurs you could end up with an infection and have tissue that needs to be removed. Additionally diabetes can result in nerve damage. This can lead to someone getting a cut or a blister that they don’t feel. Unnoticed, it can get infected and result in something like gangrene in bad cases. The reduced blood flow will slow the healing process of injuries.

Yes diabetes can. . . it also can cause kidney damage.

And vision loss. And heart problems.

An acquaintance of mine ignored sores on her feet and died of sepsis. The main cause of amputation is gangrene.